Derrick for ships



May 27, 1969 w. L. BANKS, JR

DERRICK FOR SHIPS Sheet I Filed July 10. 1967 JNVE'NTUR B W/Z LIA/7 L.BANKj'J/P.

AGENT May 27, 1969 w. L. BANKS, JR

DERRICK FOR SHIPS Sheet Filed July 10, 1967 May 27, 1969 w. L. BANKS, JR

7 DERRICK FOR SHIPS Sheet Filed July 10. 1967 7, 1969 w. L. BANKS, JR3,446,362

DERRICK FOR SHIPS Filed July 10, 1967 JNVE/V TOR WILL/Al? L. BANK-5J1?en M AGENT United States Patent US. Cl. 212-3 8 Claims ABSTRACT OF THEDISCLOSURE upon turning winch drums afiixed on deck or below deck,

said derrick providing a lifting movement of the boom and said turntablemounted around the base of the mast to support the lower end of the boomand permit a rotation of the base of the boom around the mast.

This invention relates to a derrick or cargo hoisting device for shipsand more particularly to an improved hoist and the manner of rigging theboom and hoist to produce the necessary positioning and movement of theboom in lifting and swinging the cargo in a rotary movement into adesired position.

This invention is related to my issued Patents 2,830,710 issued April15, 1958 and 2,944,680 issued July 12, 1960.

In the operation of a single boom of a derrick due to the hazardousconditions that exist on shipboard whether the ship is docked or at sea,it has been necessary to provide guy ropes so that a definite control ofthe swinging movement of the boom is retained at all times. Likewise inburtoning gear where two booms are utilized, guy ropes are provided foreach boom so that the cargo handled between booms can be very carefullypositioned and an absolute control of the swinging movement of bothbooms is retained at all times. In the present invention the rigging ofthe boom has been changed to provide the same degree of control on theswinging movement of the boom without the use of guy ropes.

It is an object of this invention to provide a derrick for a ship inwhich the rigging is comprised of a double topping lift to produce thenecessary lifting movement of the boom and a controlled swinging rangeof the boom over 360.

It is a further object of this invention to provide a hoisting apparatusfor ships in which the rigging is comprised of a double topping lift andin which the double topping lift is connected to the boom at the freeend and is connected to a pair of swinging swivel elements that arespaced apart and attached to the top of the mast at either side thereof.

It is a further object of this invention to provide a hoisting apparatusfor ships in which the rigging is comprised of a double topping lift andin which the double topping lift is connected to the boom at the freeend and is connected to a pair of swinging swivel elements that areconnected to the top of the mast and positioned either side of the boomand in which a topping lift may swing through 90 to a null point and beforced through its null point to swing an additional 90".

It is a further object of this invention to provide a derrick for a shipin which the boom is mounted at its base on a turntable whose center isthe mast center and in which the pivotal supporting attachment for therigging is positioned either side of the mast and in which the riggingincludes a double topping lift to produce the necessary lifting movementof the boom and a controlled swinging range in an arc of 360.

It is a further object of this invention to provide a derrick for a shipin which the boom is mounted at its base on a turntable that ispositioned about the mast center and in which the pivotal supportingattachment for the rigging is positioned either side of the mast and inwhich the rigging includes a double topping lift to produce thenecessary lifting movement of the boom and a controlled swinging rangein an arc of 360.

It is a further object of this invention to provide a derrick for a shipin which the boom is mounted at its base on a turntable whose center isthe mast center and in which the pivotal supporting attachment for therigging is a pair of swivel elements that are positioned either side ofthe boom and attached to the top of the mast and in which this riggingis a double topping lift to produce the necessary lifting movement ofthe boom and a controlled swinging range in an arc of 360.

It is a still further object of this invention to provide a hoistingapparatus for a ship in which the boom is mounted at its base on aturntable whose center is the mast center and in which a pair of swivelsare mounted at the top of the mast on either side thereof and in whichthe rigging and the swivels are the double topping lift and in which thedouble topping lift is connected to the boom at one end thereof and isconnected to the pair of swivel elements that are spaced apart eitherside of the mast to swing through 360.

A still further object of this invention is to provide a hoistingapparatus for ships in which the rigging is comprised of a doubletopping lift and in which the double topping lift is connected to theboom at one end thereof and is connected to a pair of swinging swivelelements that are spaced apart either side of the mast and attached to amast housing at the top of the mast and in which the double topping liftincludes two lines to a turning drum affixed on deck and in which thetwo lines are rove on the winch drum in opposite directions so that thedrum produces a shortening or lengthening of the lines to provide abridling effect on the boom head.

A still further object of this invention is to provide a hoistingapparatus for ships in which the rigging is comprised of a doubletopping lift and in which the double topping lift is connected to theboom at one end thereof and is pivotally connected to a mast housing atthe top of the mast and in which the double topping lift includes twolines to a turning drum afiixed on deck or in the hold and in which thetwo lines are rove on the winch drum in opposite directions so that thedrum produces a shortening or lengthening of the lines to provide abridling effect on the boom head.

It is a further object of this invention to provide a hoisting apparatusfor ships in which the rigging is comprised of a double topping lift andin which the double topping lift is connected to the boom at one endthereof and is pivotally connected to a pair of swivel elements that arespaced apart either side of the mast at the top of the mast and in whichthe double topping lift includes two drums afiixed on deck or in thehold for the hauling operation and in which the two drums are operatedon a shaft so that the boom may be topped or lowered while swinging andin which the hauling line also is rove on a winch drum in oppositedirections so that the drum produces a shortening or lengthening of thelines to provide a swinging of the boom in either direction while beingtopped or lowered.

it is a further object of this invention to provide a hoistlng apparatusfor ships in which the rigging is comprised of a double topping lift andin which the double topping lift is connected to the boom at one endthereof and is connected to a pair of swivel elements that are spacedapart either side of the mast and pivotally attached to a mast housingand in which the double topping lift includes two drums afiixed on deckfor the houling operation and in which the two drums are operated on asingle shaft so that the boom may be topped or lowered while swingingand in which the topping lift includes two lines that are rove on awinch drum in opposite directions so that the drum produces a shorteningor lengthening of the lines to provide a swinging of the boom inboardeither side of the outboard position.

It is a further object of this invention to provide a hoisting apparatusfor ships in which the rigging is comprised of a double topping lift andin which the double topping lift is connected to the boom at one endthereof and is connected to a pair of swivel elements that are spacedapart either side of the mast and at the top of the mast and in whichthere are provided sheaves, two for each swivel arm, and in which thedouble topping lift includes two lines that are rove on a winch drum inopposite directions so that the drum produces a shortening orlengthening of the lines to provide a swinging of the boom in eitherdirection.

A further object of this invention is to provide a derrick for a ship inwhich the rigging is comprised of a double topping lift on top of themast to produce the necessary lifting movement of the boom and acontrolled swinging range of the boom and in which all rigging lines areinternal passing from below deck through the hollow center of the mast.

It is an object of this invention to provide a derrick for a ship inwhich the rigging is comprised of a double topping lift to produce thenecessary lifting movement of the boom and a turntable mounted aroundthe base of the mast to support the lower end of the boom and permit arotation of the boom around the mast.

It is a still further object of this invention to provide a derrick fora ship in which the rigging is comprised of a double topping lift toproduce the necessary lifting and slowing movement of the boom and inwhich the double topping lift includes two swivel arms that are spacedapart either side of the mast and at the top of the mast and in whichsaid boom may be swung 90 either side of said mast with said slowingcontrol to reach a null point which is the limit of the swinging orrotation by said control and in which auxiliary means are provided tocarry the pivotally moving topping lift arm through the null point toallow said arm to drop in said next sector of rotary control and resumethe slowing control.

Other objects of this invention may be apparent by reference to theaccompanying detailed description and the drawings in which FIG. 1 is aside elevational view of the cargo hoisting device,

FIG. 2 is a front elevational view partially in cross section taken online 2-2 of FIG. 1,

FIG. 3 is a plan view taken on line 3-3 of FIG. 1,

FIG. 4 is an enlarged exploded view partially in cross section of oneside of the mast head housing and swivel arm taken on line 4-4 of FIG.1,

FIG. 5 is an enlarged elevational view taken on line 5-5 of FIG. 1,

FIG. 6 is a plan view taken on line 6-6 of FIG. 5,

FIG. 7 is a side elevational view taken on line 7-7 of FIG. 6,

FIG. 8 is a schematic illustration of a further embodiment of the masthead housing,

FIG. 9 is a schematic illustration of the tackle cables in frontelevation,

FIG. 10 is a side elevational view on line 10-10' of FIG. 6,

FIG. 11 is a schematic wiring diagram showing a motor drive clockwise,and

FIG. 12 is a schematic wiring diagram showing a motor drivecounter-clockwise.

Referring to FIGS. 1, 2 and 3 there is illustrated a hol low ship mast10 in which a mast housing 11 is mounted at the top of the mast. Aturntable 12 is affixed in a stationary relationship at or near the baseof the mast. The turntable 12 is provided with a rotatable ring 13surrounding the mast and supported on rollers 12A on the turntable 12.The turntable ring 13 is provided with a pair of pivotal supports 14 oneither side of the mast in aligned relationship for mounting the base ofthe boom 15, the boom 15 formed as a two pronged fork, each prong 14Aprovided with a clevis end 14B so that the end may be pivotally attachedand supported on the pivotal supports 14 of the ring 13. This permits arotation of the base of the boom 15 about mast 10 and with the pivotallysupported heel or lower end of the boom permits a swinging and liftingmovement of the boom in its normal operation. Boom 15 at its top end isprovided with a yoke 16 that is pivotally attached to the end of theboom. Yoke 16 is comprised of two arms 16A and 16B that are pivotallymovable about a pin 17. Each of the arms 16A and 16B are provided withsingle blocks 18A and 18B. The boom 15 at its upper end is also providedwith a single block 19. The mast housing 11 is permanently aflixed tothe top of the mast 10. The mast housing 11 is formed boxlike withparallel sides 11A and 11B on either side of the mast. These sides 11Aand 11B are used to mount a pair of topping lift arms 20 and 21 whilethe top of the housing 11 supports a single block 22 that is used tosupport the purchase cable 23 that passes through the center of thehollow mast 10 to a sheave 24 at the base or under mast 10 and in turnis mounted upon a takeup winch 25 that controls the lifting and loweringby the purchase cable 23. Purchase cable 23 extends from the top of themast over the single block 19 in the boom to a double block whichsupports the cargo or derrick hook 31, the purchase cable extending fromblock 30 to a single block 18B and back down to be affixed to thesupporting framework of 31 which supports block 30. Thus when winch 25is rotated to take in the purchase cable, hook 31 will be raised. While,if winch 25 lets out cable 23, book 31 will drop. Another form ofmounting the purchase cable when only 180 of travel is required is alsoshown in which the cable from winch 25 extends through the deck notthrough the mast passing over a pulley 70 that is mounted to turntable12. Cable 23 may then extend parallel to the boom 15 passing over theblock at 18B and extending down to the block 30 of the hook 31 andextending back up to block 18B. Thus when winch 25 takes up cable 23, itwill lift hook 31 or when cable 25 is let out, it will drop hook 31. Themast housing 11 (FIGS. 4, 5, 6 and 7) is provided with rotary mountedsupports 32 on either side 11A and 11B of the mast. The rotary support32 extends through a bore 33 in the housing with a hollow stem 34 and issupported by a bearing 35 to be freely rotatable in the bore 33. Toretain rotary support 32 in this relationship, there is a spacer 36 anda nut 37 threadably secured to the end of the stem 34. Element 32 canrotate 360. Element 32 is provided with a pivotal pin support 38 used topivotally attach the topping lift arms 20 and 21, the topping lift arms20 and 21 having a pin 39 that passes through support 38 'as well as twosupports 40 and 41 on the topping lift arm. The rotary support 32 isalso provided with a pair of supports 42 to support a pm 43. Pin 43supporting a pair of sheaves 44 and 45 which is a double blockarrangement to carry the topping lift cable. The topping lift includes apair of arms 20 and 21. At the upper end of arms 20 and 21 there isprovided a swivel support element 56, element 56 provided with a stem 57that extends into arm 20 and is anchored within arm 20 by a block 58 andnut 59 that is threadably secured to stem 57. Element 56 at its outerend supports a double block consisting of two sheaves 54 and 60. If werefer to FIG. 9 and consider a single cable 46, we may assume that thecable 46 has been rove on the drum of the winch 48A. The cable may bepassed around a lead sheave 62A up the mast through the further leadsheaves 61A, 44A and through the topping lift arm 20 through lead sheave60A extending to the single block 18A at the top of the boom and fromthe block 18A the cable will go back over a lead sheave 54A and continueover a lead sheave 45A and continue over a lead sheave 50A and down themast and pass in a clockwise direction around the drum of winch 65 fortwo or three or more turns and the cable 46 will extend from the drum ofwinch 65 up the mast over a lead sheave 50B over a second lead sheave458 through the topping lift arm over a lead sheave 5413 up to thesingle block 18B at the top of the boom extending from block 18B downover a lead sheave 60B over lead sheave 44B and 61B and down through themast to a lead sheave 628 to the drum of winch 4813 to be rove on thisdrum in the same direction as the cable is rove on drum 48A. Thiscompletes the tackle for operating the movement of the boom 15. It isapparent that the operation of the winch drums 48A and 48B in aclockwise direction will take up cable or line and thus produce ashortening of the topping lift which in turn produces a lifting of theboom 15 while operation of the winch drums 48A and 48B in acounter-clockwise direction will release cable 46 lengthening thetopping lift and allowing boom 15 to drop. With the winch drums 48A and48B stationary, it is apparent that operation of the winch drum 65clockwise will affect a movement of cable 46 producing a pull on the oneside of the topping lift to the boom while releasing the cable 46 on theopposite side of the topping lift to boom 15. This will thereforeproduce a swinging movement of boom 15 and the direction of movementwill be based upon the direction of rotation of winch 65. A clockwiserotation may produce a swinging of the boom to the right of a centerposition while a counter-clockwise rotation may produce a swinging ofthe boom 15 to the left to center position. The degree of swingingmovement of boom 15 is not limited due to the fact that, if the boom isswung to the right 90, it reaches a null point and the boom should be ina raised positioned at the null point. It is apparent that the base ofthe boom will likewise move to this position as it is free to rotate.With means to be described later, the boom may be carried past the nullpoint. To continue rotation in a further 90 sector, the winches 48A and488 must be reversed thus letting out cable on the one side to allow theboom to drop while continuing to swing in a rotation to the right whiletaking in cable on the opposite side of winch 65. Thus it is apparentthat boom 15 may be controlled in its movement 90 either side of itsstarting position and the boom 15 may be raised on either side to itsfull 90 or null point and, by auxiliary means to be described, carriedover the null point and due to the rotation of the base of the boom, itis in a new position to continue operation of the boom for 90 eitherside of the null point established. It is to be further noted that,although the boom may swing from a starting position 90 and reaching anull point, swing an additional 90, it is not intended that the boomcontinue to rotate in one direction about mast but rather that the boommay be swung either side of mast 10 to reach a position 180 from itsstarting position. It is to be noted, referring to FIG. 1, that thetopping lift arms 20 and 21 may swing from a starting position in whichthe boom is dropped to its lowest horizontal position and in liftingboom either side of mast 10 to an upright vertical position and movingpast the null point may be dropped on the opposite side dropping theboom to its lowermost horizontal position thus completing an arc withthe boom of 180. The rotation of the base of the boom permits thisoperation without hindrance. The boom 15 may be rotated 180 asillustrated in FIG. 3 in a smaller are as illustrated in a dotted lineYY. It is to be noted that the boom 15 is longer than the mast 10 thusit will extend in its raised position to a greater height than the topof the mast thus the pivotal mounting of the topping lift arms is mostimportant. This pivotal connection permits the topping lift arms 20 and21 to move in an arc shown by dotted lines ZZ, FIG. 1, so that the endof the boom may move from any position well above the end of the mast toa horizontal position that is parallel with the deck of a ship and inany position, the topping lift will produce a straight pull from theends of the topping'lift arms. It is to be noted in FIG. 1 with theraising of the boom 15 when boom 15 rises, the swivel arms 20 and 21 arepivotally moved to provide a direct pull upon the end of the boom andsince the boom is longer than the mast, as the boom continues to rise,the topping lift arms 20 and 21 continue to move counter-clockwise untilthe boom reaches a vertical position. However winch 65 must be operatedto move the boom either to the left or to the right to reach thevertical position which is the null point on the operation of the boomand the limit of travel by winches 48A and 48B. From this null point thewinches must be reversed to either drop the boom back in the same sectoror having passed the null point, to drop the boom back in the next 90sector. The topping lift arms can work together in their movement with astraight lift as in FIG. 3 from a horizontal position moving up, butwhen the boom is swung say counter-clockwise, the left hand lift 20 willpull while the right 'hand lift 21 lets out cable thus 20 will risewhile 21 will lag or remain. The position of the boom when in the middleof the starting sector will be an equal pull by both topping lifts. Ifthe boom is swung counter-clockwise, arm 20 pulls or takes in cablewhile arm 21 lets out an equal amount of cable. If the boom is risingwhile swinging, arm 20 will rise with the rise of the boom and will liftas shown in dotted lines but arm 21 will lag as it lets out cable forswinging and will not lift because it is letting out cable, thus arms 20and 21 will not be aligned until the base of the boom moves to followthe swing and the arms again equalize their lift. With the topping ofthe boom when it reaches its 90 travel, it reaches a null point and thearm 20 cannot pull any further and the cable has reached the end of itspulling. At this point an additional force is required to carry thetopping lift 20 past the null point. The additional force is provided bythe mechanism shown in FIGS. 5, 6, 7, 10 and the circuit diagrams ofFIGS. 11 and 12. If the arm or lift 20 is rotated until it reaches thenull point, the winch must be reversed so that the cable is then payedout to allow the boom to fall into the next 90 sector for its swing. Thebase of the boom will rotate on the turntable following the swing of theboom, and finally both arms will be equalized in their supportingposition.

Although the movement of the boom from horizontal to vertical is quitesimple, the swinging of the boom 90 either side of a starting centerpresents problems. We find the upright dead center position much toosharp with an almost direct pull from the top of the mast. To improveupon this vertical plane of rotation of the base of the topping liftarms, the further embodiment shown in FIG. 8 may be utilized. With thefaces 11A and 11B set at an angle to the centerline of the mast, that isspaced further apart at the top, the base of each topping lift willswing in a plane that is at an angle to the centerline of the mast. Thiskeeps the topping lift when at its highest point out and away from thecentral pull of the cable coming out of the mast and improves thecontrol.

Referring to FIGS. 5, 6 and 7 there is illustrated one approach toprovide the means to carry the topping lift arms 20 or 21 past the nullpoint and in turn carry the boom past the null point for operation inthe next 90 sector. The rotary supports 32 provide an additional function, they are formed in their periphery as a gear or gear segment 32A.A reversible motor 80 is mounted on top of the mast head housing 11. Thereversible motor 80 is provided with a pair of centrifugal clutches 81so that the motor drive produces engagement of the clutch and relaxingof the clutch with the motor drive stopping. Thus :motor 80 may drive ashaft 81 on either side of motor 80, shaft 81 being supported in abearing 82, shaft 81 extending into a gear reduction housing 83, shaft81 being afiixed to a pinion gear 84 within housing 83, pinion gear 84meshing with a reduction gear 85 also within housing 83, gear 85 beingmounted on a shaft 86, shaft 86 being supported in a bearing 87, shaft86 having at its other end a pinion gear 88, gear 88 meshing with theperiphery gear 32A thus providing the means of driving the rotarysupport 32 through an arc of rotation, that is, the actual drive ispicked up at a selected point as illustrated in FIG. 10. With therotation of the rotary support 32 clockwise, a pair of mechanicallyactuated switches A & C are provided and are mounted on the faces 11Aand 11B while an actuating roller 90 is aflixed to the apron of therotary suuport 32 to be rotated with the rotation of gear 32A. As thearm or 21 rises to ward the null point, it will reach a sector S-S whichestablishes the positioning points for switches A & C so that as therotary support 32 rotates clockwise, roller 90 will contact switch Apivotally flipping switch A from its off position to its on position.This energizes motor 80 according to the circuit shown in FIG. 11, thatis, with the motor 80 connected to a contact 92, switch A will move acontact arm 93 from its oif position to its on position closing thecircuit through a line 94 through battery B to a ground. The oppositeside of motor 80 is connected through switch C through a switch arm 95to ground. The motor 80 when energized will operate and cause itscentrifugal clutch 80A to engage and rotate shaft 81 and in turn gear 84which rotates gear 85 at a reduced speed, gear 85 in turn rotating gear88 which engages gear 32A of the rotary support thus carrying arm 20 or21 as the case may be in a continued clockwise direction through thenull point and after passing the null point, the roller 90 will contactswitch C flipping or pivotally moving switch C from its on position orgrounded position to its off position as shown in FIG. 11. When 95 ispivotally moved, it also moves an arm 96 which is connected to ground onone side and closes a circuit through contact 97 and line 98 to thewinch motor 65M. The opposite side of winch motor 65M is connectedthrough a line 99 to battery B and ground. Thus winch 65 may be operatedafter the arm 20 or 21 is carried through the null point to continuerotation and movement of the boom in the next sector of operation. Ifmotor 80 is reversed, that is, if arm 20 or 21 is now to be rotatedcounter-clockwise, the rotary support 32 will rotate counter-clockwiseunder the drive of winch 65 and motor 65M. When roller 90 contactsswitch C, it will pivotally move switch C from its off position to itson position closing arm 100 to contact 101 closing the circuit frommotor 80 through the battery to ground, the opposite side of motor 80being connected through a switch arm 102 to ground to rotate motor 80 ina counter-clockwise direction. Motor 80, through its centrifugal clutch80A, will, as in the previous sequence, drive shaft 81, gear 84 to inturn drive gear 85 and gear 88 to in turn drive the gear 32A to move thearm 20 or 21 in its clockwise movement through the null point. When arm20 or 21 moves through the null point, roller 90 will contact switch Apivotally moving switch A from its on position to its off position. Whenarm 102 is moved, it also moves an arm 103 which is connected to groundon one side and closes a circuit through contact 104 and line 105 to thewinch motor 65M. The opposite side of winch motor 65M is connected to aline 99 to battery B and ground. Thus winch 65 may be operated after thearm 20 or 21 is carried through the null point to continue rotation andmovement of the boom in a counter-clockwise movement in the next sectorof operation. Thus the movement of arm 20 or 21 by means of winch 65either clockwise or counter-clockwise reaches a range of operation inthe proximity of the null point where the reversible motor 80 takes overand 65 reaches the limit of its control. And when the arm 20 or 21 iscarried through the null point, the switches A or C out out motor andreturn the control to motor 65M of winch 65 to continue operation in thenext 180 sector in which the boom has passed. A reversal of winch 65will provide the operator with the same directional control, but theoperator must about face to follow the boom in the new 180 of movement.

Although we have described a derrick with a single mast having a pair oftopping lifts located at the top of the mast and connected to a boom itshall be understood that this arrangement shall apply to any frameworkor superstructure that may be utilized in place of a mast and althoughwe have described a single mast and double topping lift for theoperation of a boom, the principles involved shall also apply where twomasts and the same components on each mast are utilized for a burtoningoperation. Although we have described a particular physical structurefor the arms of a topping lift, the shape, the size and the curvature ofthe arms may vary without departing from the spirit of this inventionand although we have described a derrick that may operate either side ofa center line, that is, if the center line is 90 to the axis of theship, the boom may be operated fore and aft. And although we havedescribed a means of rotating the boom from one sector of operation tothe next sector of thus providing a complete 360 of operation, it is tobe understood that the means of accomplishing this rotation may bevaried without departing from the spirit of this invention. And althoughwe have shown simplified circuits and components to produce the desiredcontrol during the rotation of the topping lift, it is to be understoodthat changes in these circuits may be made to assist in this operationwithout departing from the spirit of this invention. And although wehave shown a means of rotating the base of the boom with respect to therotation of the topping lift, changes may be made in the mounting andmeans of rotation of the base of the boom without departing from thespirit of this invention.

What is claimed is:

1. A derrick for a ship which includes a mast and boom, a pair ofindependently rotatable topping lift arms positioned either side of themast at the head of the mast, a pair of topping lift winches and cableto haul and lift the boom, a purchase winch and cable to lift the cargoand a rotation winch and cable to rotate said boom, each of said toppinglift arms supporting a sheave at its outer end and said boom supportinga sheave at its outer end, said cable from said topping lift winchesrove through the sheaves and said topping lift winches to be movable inopposite directions to control the swing of said boom, one of saidtopping lift arms rotatable from a forward position with the lifting andswinging of the boom toward one side, the other topping lift armrotatable only by the lifting of the boom, a turntable on said mast tosupport the base of said boom and retain said boom in an alignment withsaid mast during rotation of said boom about said mast, said boomswingable from a forward axis in front of the mast to 90 either side ofthe mast, said boom raised during its 90 swing to reach the limit of thetopping lift winch travel and the limit of the cable pull to reach anull position, a reversible motor and drive mounted at the top of themast and connected to each topping lift arm, means to rotate either ofsaid topping lift arms to carry it past the null position and means todrop said boom away from the null position and move said boom into thenext sector of rotation.

2. In a device according to claim 1 in which said mast is tubular andsaid cable from said winches passes through the center of the tubularmast.

3. In a device according to claim 1 in which said topping lift arms arealso pivotally connected to the rotary mounting to move from a closedposition on the rotary mounting to an open position according to thepull of the cable from the end of the boom.

4. In a device according to claim 1 in which said boom is swingable 90either side of a center line and movable from a horizontal position toan approximately vertical position and in which said boom may be eitherlifted or lowered while rotating by controlling a single cable that isrove on both the topping lift winches and the rotation winch.

5. In a device according to claim 1 in which the topping lift armsrotate in an arc of 270 and in which one topping lift arm is in a closedposition while the boom swings through the central portion of its arc oftravel and the opposite topping lift arm is pivotally movable to an openposition when the swing of the boom is to the side toward the arm thatopens.

6. In a device according to claim 1 in which the boom is operative forlifting in one sector of 180 but is movable into a second sector of 180that is 90 removed from its original sector and in which said boom isagain movable into a new sector of 180 that is 90 removed from itssecond sector to provide 360 of rotation for operation of said boom.

7. In a device according to claim 1 in which the means to urge said boomto move through its null point of operation includes a reversible motorwith automatic engaging clutches connected to reduction gears which arein turn connected to means to rotate said topping lift arms and a pairof switches that are actuated by the movement of said topping lift armsto control the on and off operation of said motor as well as thedirection of rotation.

8. In a device according to claim 7 in which there is a reversible motordrive on said rotation winch and said switches also reverse theoperation of said reversible motor to lower said boom while continuingto travel in the same rotation.

References Cited UNITED STATES PATENTS 2,830,170 4/1958 Banks 2123FOREIGN PATENTS 1,020,170 11/1957 Germany.

1,094,617 12/1960 Germany.

RICHARD E. AEGERTER, Primary Examiner. HARVEY C. HORNSBY, AssistantExaminer.

U.S. Cl. X.R. 212--58, 144

